Anti-obesity devices

ABSTRACT

Method and apparatus for limiting absorption of food products in specific parts of the digestive system is presented. A gastrointestinal implant device is anchored in the pyloric portion of the gastrointestinal system and extends beyond the ligament of Treitz. All food exiting the stomach is funneled through the device. The gastrointestinal device includes an anchor for anchoring the device in the pyloric portion and a flexible sleeve that extents into the duodenum. The anchor is collapsible for endoscopic delivery and removal.

This application is a continuation of U.S. application Ser. No.11/635,890, filed Dec. 8, 2006, now U.S. Pat. No. 8,486,153 which is adivisional of U.S. application Ser. No. 11/541,616, filed Oct. 2, 2006,now U.S. Pat. No. 7,766,861, which is a divisional of U.S. applicationSer. No. 10/726,011, filed on Dec. 2, 2003, now U.S. Pat. No. 7,122,058,which claims the benefit of U.S. Provisional Application No. 60/512,145,filed on Oct. 17, 2003.

The entire teachings of the above applications are incorporated hereinby reference.

BACKGROUND OF THE INVENTION

According to the Center for Disease Control (CDC), over sixty percent ofthe United States population is overweight, and almost twenty percentare obese. This translates into 38.8 million adults in the United Stateswith a Body Mass Index (BMI) of 30 or above. The BMI is defined as aperson's weight (in kilograms) divided by height (in meters), squared.To be considered clinically, morbidly obese, one must meet one of threecriteria: BMI over 35, 100 lbs. overweight or 100% above ideal bodyweight. There is also a category for the super-obese for those weighingover 350 lbs.

Obesity is an overwhelming health problem. Because of the enormousstrain associated with carrying this excess weight, organs are affected,as are the nervous and circulatory systems. In 2000, the NationalInstitute of Diabetes, Digestive and Kidney Diseases (NIDDK) estimatedthat there were 280,000 deaths directly related to obesity. The NIDDKfurther estimated that the direct cost of healthcare in the USassociated with obesity is $51 billion. In addition, Americans spend $33billion per year on weight loss products. In spite of this economic costand consumer commitment, the prevalence of obesity continues to rise atalarming rates. From 1991 to 2000, obesity in the US grew by 61%. Notexclusively a US problem, worldwide obesity ranges are also increasingdramatically.

One of the principle costs to the healthcare system stems from theco-morbidities associated with obesity. Type-2 diabetes has climbed to7.3% of the population. Of those persons with Type-2 diabetes, almosthalf are clinically obese, and two thirds are approaching obese. Otherco-morbidities include hypertension, coronary artery disease,hypercholesteremia, sleep apnea and pulmonary hypertension.

Although the physiology and psychology of obesity are complex, themedical consensus is that the cause is quite simple—an over intake ofcalories combined with a reduction in energy expenditures seen in modernsociety. While the treatment seems quite intuitive, the institution of acure is a complex issue that has so far vexed the best efforts ofmedical science. Dieting is not an adequate long-term solution for mostpeople. Once an individual has slipped past the BMI of 30, significantchanges in lifestyle are the only solution.

There have been many attempts in the past to surgically modify patients'anatomies to attack the consumption problem by reducing the desire toeat. Stomach saplings, or gastroplasties, to reduce the volumetric sizeof the stomach, therein achieving faster satiety, were performed in the1980's and early 1990's. Although able to achieve early weight loss,sustained reduction was not obtained. The reasons are not all known, butare believed related to several factors. One of which is that thestomach stretches over time increasing volume while psychologicaldrivers motivate patients to find creative approaches to literally eataround the smaller pouch.

There are currently two surgical procedures that successfully producelong-term weight loss; the Roux-en-Y gastric bypass and thebiliopancreatic diversion with duodenal switch (BPD). Both proceduresreduce the size of the stomach plus shorten the effective-length ofintestine available for nutrient absorption. Reduction of the stomachsize reduces stomach capacity and the ability of the patient to take infood. Bypassing the duodenum makes it more difficult to digest fats,high sugar and carbohydrate rich foods. One objective of the surgery isto provide feedback to the patient by producing a dumping syndrome ifthey do eat these food products. Dumping occurs when carbohydratesdirectly enter the jejunum without being first conditioned in theduodenum. The result is that a large quantity of fluid is dischargedinto the food from the intestinal lining. The total effect makes thepatient feel light-headed and results in severe diarrhea. For reasonsthat have not been determined the procedure also has an immediatetherapeutic effect on diabetes.

Although the physiology seems simple, the exact mechanism of action inthese procedures is not understood. Current theory is that negativefeedback is provided from both regurgitation into the esophagus anddumping when large volumes of the wrong foods are eaten. Eventually,patients learn that to avoid both these issues they must be compliantwith the dietary restrictions imposed by their modified anatomy. In theBPD procedure, large lengths of jejunum are bypassed resulting inmalabsorption and therefore, reduced caloric uptake. In fact, thestomach is not reduced in size as much in the BPD procedure so that thepatient is able to consume sufficient quantities of food to compensatefor the reduced absorption. This procedure is reserved for the mostmorbidly obese as there are several serious side effects of prolongedmalabsorption.

Unfortunately, these procedures carry a heavy toll. The morbidity ratefor surgical procedures is alarmingly high with 11% requiring surgicalintervention for correction. Early small bowel obstruction occurs at arate of between 2-6% in these surgeries and mortality rates are reportedto be approximately 0.5-1.5%. While surgery seems to be an effectiveanswer, the current invasive procedures are not acceptable with thesecomplication rates. Laparoscopic techniques applied to these surgeriesprovide fewer surgical complications but continue to expose these veryill patients to high operative risk in addition to requiring an enormouslevel of skill by the surgeon. Devices to reduce absorption in the smallintestines have been proposed (See U.S. Pat. No. 5,820,584 (Crabb), U.S.Pat. No. 5,306,300 (Berry) and U.S. Pat. No. 4,315,509 (Smit)). However,these devices have not been successfully implemented.

SUMMARY OF THE INVENTION

The present invention provides a method and apparatus for theapplication of a barrier sleeve in the digestive tract to limitabsorption of food products in specific parts of the digestive tract andto provide negative feedback to patients with morbid obesity enablingthem to modify their heating habits.

A gastrointestinal implant device can be inserted endoscopically incombination with a delivery catheter. The delivery catheter includes acatheter for passage through the intestines and a spherically shapedelement coupled to the distal end of the catheter. The sphericallyshaped element may be remotely releasable.

A delivery system for placing a gastrointestinal implant device in abody includes an outer sheath in the proximal portion of the deliverysystem for storing a proximal portion of the gastrointestinal implantdevice. The proximal portion of the gastrointestinal implant deviceincludes an anchoring device for anchoring the device in the stomach.The delivery system includes an inner sheath within the outer sheath.The inner sheath extends beyond the outer sheath toward the distal endof the delivery system. A first lumen is within the inner sheath forpassing the outer sheath over a guidewire and a second lumen is withinthe inner sheath for moving a moveable element to secure the distal endof a sleeve coupled to the stent to the inner sheath. The deliverysystem also includes a release mechanism to release the anchoring devicefrom the outer sheath. A sleeve release mechanism is coupled to themoveable element for releasing the distal end of the sleeve. There is aspherical shaped element at the distal end of the delivery system whichis held by the moveable element.

The moveable element may be a sleeve retention wire, which exits thesecond lumen and pierces the distal end of the sleeve. The sleeverelease mechanism pulls the outer sheath toward the proximal end of thedelivery system to remove the outer sheath from the anchoring device.The sleeve release mechanism pulls the moveable element toward theproximal end of the delivery system to release the distal end of thesleeve after the anchoring device has been released.

A distal portion of the sleeve may be stored in a pill for delivery andthe distal portion of the sleeve is released from the pill byperistalsis. The distal portion of the sleeve may be stored in adissolvable pill for delivery. The spherical shaped element is attachedto an element retention wire which is held by the moveable element. Themoveable element may be looped through the spherical shaped element, thedistal end of the moveable element may be coiled and stored within thespherical shaped element or the moveable element may be held in anS-shaped track within the spherical shaped element.

The spherical shaped element at the distal end of the delivery systemmay be an expandable balloon. The element may be remotely releasable.The inner sheath may include a third lumen through which a fluid ispassed to release the sleeve from the distal end of the delivery device.The sleeve release mechanism pulls the moveable element toward theproximal end of the delivery system to release the spherical shapedelement after the anchoring device has been released.

A gastrointestinal implant device includes a flexible sleeve and acollapsible anchor coupled to a proximal end of the sleeve. The flexiblesleeve is open at both ends, and adapted to extend into the duodenum tolimit absorption of nutrients in the duodenum. The anchor includes twospaced apart rings of differing diameters to anchor the proximal portionof the sleeve in the stomach. The rings may be made from Nitinol and mayinclude at least two stabilizing ears and may be formed by looselyintertwined wires. The rings may be linked with a connecting bar. Theconnecting bar includes extensions extending from the exterior surfaceof the bar for anchoring the proximal portion of the sleeve in thestomach. Extensions extending from the exterior surface of a proximalring and extensions extending from the exterior surface of a distal ringare angled towards each other. The anchor is covered by a proximalportion of the sleeve. The interior surface of the ring is covered bythe sleeve and the exterior surface of the ring is coated withpolyurethane. The rings are folded in a u-shape stored in a deliverytube to insert the flexible sleeve.

The sleeve may be impregnated with an anti-hunger hormone such aspeptide-YY. The sleeve may be impregnated with a drug that reducesinflammation. The distance between the rings may be selected to hold thepylorus open. The sleeve may be formed of low friction materials such ascast polytetrafluoroethylene, polytetrafluoroethylene, cast fluoronatedethylene propylene with polytetrafluoroethylene coating, extrudedfluoronated ethylene propylene and extruded perfluoroalkoxy.

The gastrointestinal implant device can be used as a method for treatingintestinal bowel disease. A flexible sleeve is anchored within thestomach. The sleeve is open at both ends and impregnated with a drugthat reduces inflammation. The flexible sleeve is into the jejunum.

The gastrointestinal implant device can be used as a method for treatingobesity. A flexible sleeve is anchored within the stomach. The sleeve isopen at both ends and enhanced with anti-hunger hormones and theflexible sleeve is extended into the duodenum.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other objects, features and advantages of theinvention will be apparent from the following more particulardescription of preferred embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention.

FIG. 1 is a sectional view of a portion of the digestive tract in abody;

FIG. 2 is a perspective view of a gastrointestinal implant deviceaccording to the principles of the present invention;

FIG. 3A is a plan view of the proximal portion of the gastrointestinalimplant device shown in FIG. 2;

FIG. 3B is a cross-sectional view as taken along line A-A of FIG. 3Ashowing the stent and first inner layer and second outer layer of thesleeve shown in FIG. 2;

FIG. 4 is a perspective view of the gastrointestinal implant device withthe second outer layer of the sleeve removed;

FIG. 5 is a sectional view of a body showing the gastrointestinalimplant device implanted in the digestive system;

FIG. 6 is a perspective view of a collapsible self-expanding stent inthe gastrointestinal implant device;

FIG. 7 is a perspective view of the stent shown in FIG. 6 whencompressed;

FIG. 8 is a perspective view of another embodiment of a stent whencompressed;

FIG. 9 is a perspective view of the stent shown in FIG. 8 with the strutends bent to provide opposed barbs;

FIG. 10 is a perspective view of the stent shown in FIG. 8 whenexpanded;

FIG. 11 illustrates the gastrointestinal device shown in FIG. 1including an anti-buckling mechanism;

FIG. 12 is a perspective view of a catheter system for delivery of thegastrointestinal implant device;

FIG. 13 is a cross-sectional view of the inner shaft taken along lineE-E of FIG. 12;

FIG. 14A is an expanded perspective view of the dead-bolt mechanismshown in FIG. 12;

FIG. 14B is a sectional view of the dead-bolt mechanism shown in FIG.13A illustrating the sleeve retention wire threaded through the sleeve;

FIG. 15 is sectional view of a portion of the catheter systemillustrating the collapsed stent stored inside the outer sheath;

FIG. 16A is a plan view of the catheter system illustrating thecollapsed stent stored inside the outer sheath of the gastrointestinalimplant device;

FIG. 16B is a plan view of the catheter system illustrating thegastrointestinal implant device after release of the stent from theouter sheath;

FIG. 16C is a plan view of the catheter system illustrating the expandedgastrointestinal implant device after the sleeve retention wire has beenreleased;

FIG. 17 is a perspective view of another embodiment of the cathetersystem shown in FIG. 12;

FIG. 18 is a sectional view of an everting catheter system for deliveryof a longer length sleeve;

FIG. 19 is a perspective view of a retrieval device for removing thegastrointestinal implant device from the digestive tract;

FIG. 20 is a perspective view of the removal device engaged with thestent;

FIG. 21 is a perspective view of another embodiment of agastrointestinal implant device;

FIG. 22 is a perspective view of the anchoring ring shown in FIG. 21;

FIG. 23 is a perspective view of the anchoring ring shown in FIG. 21 ina collapsed position for insertion and removal;

FIG. 24 is a perspective view of an anchor for anchoring the collapsiblering shown in FIG. 23 to the muscular tissue of the pyloric section ofthe stomach;

FIG. 25A is a perspective view of a delivery system for delivering theanchor after the gastrointestinal implant device has been placed in thestomach;

FIG. 25B is a plan view of the delivery system shown in FIG. 25A;

FIG. 25C is a cross-sectional view of the distal end of the catheter astaken along line B-B of FIG. 25A;

FIG. 25D is a perspective view of the gastrointestinal implant deviceillustrating the anchor engaged with the tissue;

FIG. 25E is an isometric view illustrating the barb engaging the tissueafter delivery;

FIG. 26A is a plan view of the delivery system including a snare wirefor holding the distal end of the sleeve in position;

FIG. 26B is a cross-sectional view taken along line CC of FIG. 26Athrough the inner sheath;

FIG. 26C is a cross-sectional view taken along line DD of FIG. 26Athrough the outer sheath showing the inner sheath within the outersheath;

FIG. 26D is a cross-sectional view through the distal portion of thecatheter showing the snare capturing the distal end of the sleeve;

FIG. 26E is a sectional view through the distal portion of the cathetershowing the snare locking mechanism;

FIG. 27 is a perspective view of the distal portion of thegastrointestinal implant device including texturing at the distal end;

FIG. 28 is a perspective view of a gastrointestinal implant device withanother embodiment of an anchoring device;

FIG. 29 is a plan view of one of the rings in the gastrointestinalimplant device shown in FIG. 28;

FIG. 30 is a perspective view of the gastrointestinal implant deviceshown in Fig. in a collapsed position in a delivery tube for deliveryinto the body;

FIG. 31 is a perspective view of the gastrointestinal implant deviceillustrating the deployment of the distal ring from the delivery tubeshown in FIG. 30;

FIG. 32 is a perspective view of the gastrointestinal implant deviceafter the deployment of the distal ring prior to deployment of theproximal ring;

FIG. 33 is a perspective view of the gastrointestinal implant deviceshown in FIG. 28 with an alternative embodiment of an anchoring device;

FIG. 34 is a plan view of the gastrointestinal implant device shown inFIG. 33;

FIG. 35 is a perspective view of another embodiment of one of theanchoring rings shown in FIG. 28;

FIG. 36 is a perspective view of a gastrointestinal implant device withyet another embodiment of an anchor;

FIG. 37 is a perspective view of the anchor shown in FIG. 36 with thesleeve removed;

FIG. 38 is a perspective view of the gastrointestinal device shown inFIG. 36 in a collapsed position in a delivery tube for delivery into thebody;

FIG. 39 is a perspective view of a delivery system illustrating thedeployment of the distal ring 2803 from the delivery tube;

FIG. 40A is a plan view of the gastrointestinal device shown in FIG. 38with additional anti-rotation and locking features;

FIG. 40B is a perspective view of the anchor shown in FIG. 40A withoutthe sleeve;

FIG. 41 is a perspective view of an alternative embodiment of agastrointestinal implant device shown in FIG. 28.

FIG. 42A is a perspective view of a portion of a catheter system fordelivery of a gastrointestinal implant device;

FIG. 42B is a cross-sectional view of the catheter shaft taken alongline 42B-42B of FIG. 42A;

FIG. 43 is a sectional view of a portion of the digestive tract in abody illustrating the position of a gastroscope/guide tube assembly;

FIG. 44 is a sectional view of a portion of the digestive tract in abody illustrating the distal end of the catheter extending from thedistal end of the guide tube 4300;

FIG. 45 is a sectional view of a portion of the digestive tract in abody after the gastroinstestinal implant device of FIG. 28 has beendelivered;

FIG. 46 is a plan view of the distal end of the catheter systemillustrating a releasable ball tip mechanism;

FIG. 47 is a plan view of the distal end of the catheter illustrating analternative embodiment of a releasable ball tip mechanism;

FIG. 48 is a plan view of the distal end of the catheter illustratingyet another embodiment of a releasable ball tip mechanism;

FIG. 49 is a cross sectional view of an alternative embodiment of asolid spherical shaped element;

FIG. 50A is a plan view of the distal end of the catheter with aninflatable spherical shaped element;

FIG. 50B is a plan view of the distal end of the catheter after theinflatable spherical shaped element has been inflated;

FIG. 51 is a plan view of an alternative delivery system for deliveringa gastrointestinal implant device;

FIG. 52 is a plan view of another embodiment of the delivery mechanismshown in FIG. 51; and

FIGS. 53A-53C illustrate a method for delivering an alternate embodimentof the catheter system 4250 having a central lumen for placement over aguide wire.

DETAILED DESCRIPTION OF THE INVENTION

A description of preferred embodiments of the invention follows. FIG. 1is a sectional view of a portion of the digestive tract in a body. Foodto be digested enters the stomach 102 through the cardiac orifice 110from the esophagus. Chyme, a semi-fluid, homogeneous creamy orgruel-like material produced by gastric digestion in the stomach exitsthe stomach through the pyloric orifice (pylorus) 108 and enters thesmall intestine 112. The pylorus 108 is a distal aperture of the stomach102 surrounded by a strong band of circular muscle. The small intestine,about nine feet in length, is a convoluted tube, extending from thepylorus to the ileo-caecal valve where it terminates in the largeintestine. The small intestine has three sections, the duodenum 104,jejunum 106 and the ileum (not shown). The first eight to ten inchsection of the small intestine, the duodenum, is the shortest, widestand most fixed part of the small intestine.

The duodenum has four sections: superior, descending, transverse andascending which typically form a U-shape. The superior section is abouttwo inches long and ends at the neck of the gall bladder. The descendingsection is about three to four inches long and includes a nipple shapedstructure (papilla of vater) 114 through which pancreatic juice from thepancreas and bile produced by the liver and stored by the gall bladderenter the duodenum from the pancreatic duct. The pancreatic juicecontains enzymes essential to protein digestion and bile dissolves theproducts of fat digestion. The ascending section is about two incheslong and forms the duodenal-jejunal flexure 116 where it joins thejejunum 106, the next section of the small intestine. Theduodenal-jejunal flexure 116 is fixed to the ligament of Treitz 118(musculus supensionus duodeni). The juices secreted in the duodenumbreak the partially digested food down into particles small enough to beabsorbed by the body. The digestive system is described in Gray'sAnatomy (“Anatomy of the Human Body”, by Henry Gray) and “HumanPhysiology”, Vander, 3^(rd) ed, McGraw Hill, 1980, the contents of whichare incorporated herein by reference in their entirety.

FIG. 2 is a perspective view of a gastrointestinal implant device 200according to the principles of the present invention. Thegastrointestinal implant device 200 includes an elongated open-endedflexible sleeve or tube 202 having a first proximal opening 204 and asecond distal opening 206. Within the sleeve 202 is a passageway thatextends from the first proximal opening 204 to the second distal opening206 for transporting the chyme exiting the stomach 102 (FIG. 1). Thesurface of the passageway (the interior surface of the implant device200) is smooth to enable the chyme to easily pass through. The exteriorsurface of the implant device 200 is smooth to prevent tissue in-growthand to be non-irritating to the bowel.

Within the implant device 200 at the proximal end including the firstproximal opening 204 is a collapsible self-expanding stent 208. Thestent 208 includes a plurality of opposed barbs 210 for anchoring theimplant device 200 to the muscular pylorus in the stomach 102. Thediameter of the stent 208 is dependent on the diameter of the pyloricorifice 108 (FIG. 1) about 0.8″ to 1.1″ based on human anatomyvariations. In one embodiment, the length l of the stent 208 is selectedto extend through the pylorus 108 and keep the pylorus 108 permanentlyopen to induce “dumping syndrome”. In an alternate embodiment, a stentwith a shorter length l allows the pylorus 108 to open and closenormally.

The sleeve material is thin and conformable so that it collapses in theintestine to a small volume to minimize bowel irritability. It has a lowcoefficient of friction (<0.20) so that chyme slides easily through itand the bowel slides easily around it. It is of low permeability tofluids so that the chyme does not touch the bowel wall and the digestiveenzymes do not significantly breakdown the chyme. It is biologicallyinert and non-irritating to the tissues. One such material is expandedpolytetrafluoroethylene (ePTFE) with a wall thickness of about 0.006″and an internodal distance of 20 microns. This material is hydrophobicbut is slightly porous. However, these very small pores may plug overtime. The porosity may be reduced by coating the material on the inside,outside or in the pores with dilute solutions of silicone orpolyurethane. Another material is polyethylene with a wall thickness ofless than 0.001″. Other materials include Cast PTFE(polytetrafluoroethylene, Teflon), Cast PTFE with FEP (fluoronatedethylene propylene) or PFA (Perfluoroalkoxy) coating to minimize pinholes, Extruded FEP and Extruded PFA. These materials are solid andnon-porous in contrast to ePTFE which is porus, but these materials arealso considered to be Teflons. Rubber-like materials typically havefriction coefficients of 1-4, significantly stickier than thesematerials. However, in alternate embodiments other materials havingsimilar characteristics can be used.

The sleeve 202 includes two layers of material at least at the proximalend. A first outer layer covers the exterior of the stent. The secondinner layer covers the interior surface of the stent 208. The barbs 210protrude from the exterior surface of the stent 208 through the firstouter layer of the sleeve 208. The holes in the first outer layerthrough which the barbs 210 protrude are filled with an imperviousmaterial such as silicone or urethane to limit mixing of digestivejuices with the chyme flowing through the passageway. The diameter ofthe sleeve 208 is selected such that the first outer layer of the sleeve208 fits over the stent 208.

The sleeve length 212 ranges from about one foot to about five feet. Thetypical length of the sleeve 208 is about 1.5 feet from the anchor(barbs 210) in the pyloric region of the stomach to below the ligamentof Treitz 118 (FIG. 1). The length 212 of the sleeve 202 is selected tobypass the duodenum 104 (FIG. 1) and a portion of the jejunum. Thelength is increased to further decrease absorption by bypassing a longersection of the jejunum 106 (FIG. 1). The length 212 of the sleeve 202 isvariable and dependent on the patient's Body Mass Index (BMI). Theprocedure is a less invasive alternative to surgery for the treatment ofobesity and morbid obesity and also provides a new treatment approachfor type 2 diabetes.

The covered stent 208 can be collapsed into a sheath having a diameterless than ¼ inch to enable endoscopic delivery. Covering the exteriorsurface of the stent 208 with the first outer layer of the sleeve 202permits endoscopic removal of the implant device 200 by preventingtissue in-growth on the exterior surface of the stent 208.

Markings can be added to the exterior surface of the sleeve 202 todetect the position and orientation of the sleeve on a fluoroscopicimage and whether the sleeve is twisted. For example, a stripe can bepainted down the length of the device 200 using tantulum impregnatedink, or tantulum bands can be bonded to the exterior surface of thedevice. If the sleeve 202 is twisted, the sleeve 202 can be untwisted byinserting a balloon into the proximal end of the device thereby sealingit, and then injecting water into the sleeve at low pressure.

FIG. 3A is a plan view of the proximal portion of the gastrointestinalimplant device shown in FIG. 2. FIG. 3B is a cross-sectional view astaken along line AA of FIG. 3A showing the stent 208 and the first outerlayer 300 and the second inner layer 302 of the sleeve 202 shown in FIG.2. As described in conjunction with FIG. 2, the sleeve 202 includes afirst outer layer 300 and a second inner layer 302. The first outerlayer 300 is bonded to the second inner layer 300 at positions 306 belowthe distal end of the stent 208 and at positions 308, above the proximalend of the stent 208. A passageway 304 inside the second inner layer 302of the sleeve 202 allows passage of chyme through the sleeve 202. Thestent 208 is sandwiched between the first outer layer 300 and the secondinner layer 302 at the proximal end of the sleeve 202 and is free tomove at the distal end within the first outer layer 300 and the secondinner layer 302 of the sleeve 202. The covered exterior surface of thestent 208 prevents tissue growth to allow removal of the implant device200. The covered interior surface of the stent 208 provides a smoothpassageway for chyme to bypass the duodenum 104.

FIG. 4 is a perspective view of the gastrointestinal implant device 200with the first outer layer 300 of the sleeve 202 removed. Theinterconnecting struts which form the mesh (a network of struts) withdiamond spaced openings are sufficiently flexible to allow the stent tobe collapsed inside a delivery catheter and have sufficient elasticityto hold the pylorus open once the catheter is withdrawn. The forceneeded to hold the pylorus open is about 1-2 lbs. of radial forceoutward when the stent is compressed from its full diameter by 25%.

FIG. 5 is a sectional view of a body showing the gastrointestinalimplant device 200 implanted in the digestive system. The first proximalend 204 of the implant device 200 is anchored to muscle in the pyloricportion of the stomach 102. The barbs 210 grip onto the muscle to anchorthe implant device 200 in place so that the implant device 200 can notbe dragged into the stomach or down into the intestines with movement ofthe stomach and the intestines.

The sleeve 202 extends over the ligament of Treitz 118 beyond theproximal jejunum. Extending the sleeve below the ligament of Treitzreduces the likelihood that the sleeve will move back through theduodenum 104 toward the stomach 102.

After the gastrointestinal implant device 200 has been placed in thebody and anchored in the pyloric portion of the stomach, chyme leavingthe stomach passes through passageway 304 (FIG. 3B) inside the sleeve202 and bypasses the duodenum and proximal jejunum. By directing thechyme through the sleeve 202 the digestion and the absorption process inthe duodenum is interrupted. By interrupting mixing of the chyme withjuices in the duodenum, partially digested food material is not brokendown into particles small enough to be absorbed by the body. Further,there is no mixing of bile with the chyme until the chyme reaches thejejunum. The absorption of fats and carbohydrates is reduced by delayingthe mixing of bile with the chyme.

The pyloric valve opens periodically to allow chyme to exit the stomach102 to the duodenum 104. In one embodiment of the invention the lengthof the stent 208 is selected to keep the pyloric valve permanently opento induce “dumping syndrome”. By keeping the pylorus open, the chymeempties rapidly into the sleeve 202 and passes down through the sleeveand into the jejunum with minimal digestion. This results in a “dumpingsyndrome” which is a reaction to excessive rapid dumping of chyme intothe jejunum causing the patient to feel ill, dizzy and nauseated. Thissyndrome is particularly enhanced when sugars and carbohydrates areeaten and passed directly into the jejunum.

To hold the pyloric valve open, the length of the stent should be atleast 1.5 inches so that the stent extends from the anchoring positionin the pyloric portion of the stomach through the pyloric orifice 108(the opening from the stomach while the pyloric valve is open). Thelength of the stent is selected so that the distal end of the stent isabove the papilla of vater 114 (FIG. 1). As shown, the stent 208 extendsthrough the pyloric orifice 108 to hold the pyloric valve permanentlyopen. In an alternative embodiment, the length of the stent 208 isselected such that the stent 208 ends at the stomach side of the pyloricorifice 108 allowing the pyloric valve to operate normally.

The sleeve 202 provides weight loss mechanisms by providing negativefeedback, reduced fat digestion and reduced desire for food. The reducedfat digestion occurs because the sleeve 202 delays the mixing of bileand pancreatic juices with chyme from the stomach until after the chymeleaves the sleeve. The reduced desire for food may occur because thesleeve 202 blocks hormonal release from the duodenum.

After the chyme from the stomach has passed through the sleeve, thesleeve becomes extremely thin and floppy, permitting the sleeve tocontour to the inner walls of the intestine. The sleeve is non-compliantand drapes away from the intestinal walls thereby permitting thepancreatic juice to flow unimpeded into the duodenum through the papillaof vater. The normal peristalsis of the bowel is used to propel thechyme through the intestines.

FIG. 6 is a perspective view of a collapsible self-expanding stent 600in the gastrointestinal implant device 200 shown in FIG. 2 whenexpanded. The stent 600 is non-woven, collapsible and self-expanding,allowing endoscopic insertion and removal of the implant device 200. Thestent 600 includes a plurality of flat struts 602 forming an open spacepattern to ease collapsing while ensuring self-expansion. The open spacepattern allows for collapsing into a catheter for endoscopic deliveryand removal. The struts 602 may be manufactured from heat-treated springsteel such as Nitinol or MP35N.

In the embodiment shown, the stent has a length L of about 1.5 inchesand has a diameter D of about 1 inch. The struts 602 are flat, about0.010 inches wide and about 0.004 to 0.010 inches thick. The stent canbe formed from a tube of material by laser cutting followed by expansionand heat setting, or other methods well known to those skilled in theart.

In an alternate embodiment, the struts 602 can be formed separately andthe strut intersections can be welded or attached by other means wellknown to those skilled in the art. Visually the struts form sections 604around the circumference of the stent. Each section has a series oftriangles with each triangle defined by one distal strut connection 606and two proximal strut connections 608, 610. The ratio of the collapseddiameter to the expanded diameter of the stent is roughly 1:4.

When expanded, the angle α between divergent strut sections is about45-50 degrees and the diameter of the stent is about one inch. Whencompressed, the angle β between divergent strut sections is about 5-6degrees to reduce the diameter of the stent to about 0.21 inch forendoscopic delivery and removal. The elasticity of the struts permitsthis compression. When the radial compression is released, theelasticity of the struts causes the stent to expand to diameter D. Thestent assumes its desired diameter as the elastic restoring forces seektheir minimum stress.

The ends of the struts at the proximal end of the stent 600 areelongated and shaped to provide barbs 612 to anchor to the muscle in thepyloric portion of the stomach 102.

FIG. 7 is a perspective view of the stent 600 shown in FIG. 6 whencompressed. The stent 600 is compressed until the angle β betweendivergent strut sections is about 5-6 degrees to reduce the diameter Dof the stent 600 to about 0.21 inch for endoscopic delivery and removal.The barbs 704 at the proximal end of the stent are elongated. The barbs704 can be shaped to anchor the stent to the muscular pylorus.

FIG. 8 is a perspective view of another embodiment of a stent 800 whencompressed. Pairs of barbs 802 at the proximal end of the stent 800 areelongated and can be shaped to provide opposed barbs to anchor the stent800 in the muscle of the pylorus.

FIG. 9 is a perspective view of the compressed stent 800 shown in FIG. 8with the strut ends 902, 900 bent to provide opposed barbs 904, 906. Thebarbs 904,906 engage the muscle of the pylorus to anchor thegastrointestinal implant device in the pylorus portion of the stomach.As shown in FIG. 2, the strut ends 900, 902 protrude outward from theouter surface of the stent 800 in opposite directions. They may beperpendicular to each other. The barbs 904, 906 at the ends of therespective opposed strut ends 900, 902 dig into the pylorus muscle toanchor the stent. The barbs 904, 906 at the end of the protrudingopposed strut ends 900, 902 prevent movement of the stent 800 in eitherdirection; that is, they prevent movement of the stent 800 into thestomach and prevent movement of the stent 800 down through the duodenum.

FIG. 10 is a perspective view of the stent 800 shown in FIG. 8 whenexpanded. As discussed in conjunction with FIG. 9, the opposed strutends 904, 906 engage the muscle of the pylorus while the stent 800 isexpanded. In the engaged position, the barbs 904, 906 spread radiallyoutward from the longitudinal axis of the stent 800 such that the tipsof the barbs come into contact and engage the tissue.

FIG. 11 illustrates the gastrointestinal device 1100 shown in FIG. 1including an anti-buckling mechanism 1102. A flexible, anti-rotation,anti-buckling mechanism 1102 is attached to the sleeve 202 and extendsfrom below the distal end of the stent along the length L of the sleeveto the distal end of the sleeve 202. In the embodiment shown, theanti-buckling mechanism 1102 is a guidewire device attached to theexterior surface of the outer layer of the flexible sleeve. Guidewiredevices are well known to those skilled in the art. A first proximal endof the guidewire device 1104 is attached below the stent and a seconddistal end of the guidewire device 1106 is attached to the distal end ofthe flexible sleeve. The diameter of the guidewire ranges from about0.010″ to about 0.016″.

The gastrointestinal implant device 200 is designed for endoscopicplacement. FIG. 12 is a perspective view of a portion of a cathetersystem 1200 for delivery of the gastrointestinal implant device. Thecatheter system follows a guide wire 1212 through the esophagus and thestomach to the pylorus portion of the stomach. The guide wire 1212enters a first inner lumen at the proximal end 1208 of the cathetersystem 1200 and exits the first inner lumen at the distal end 1222 ofthe catheter system 1200.

The catheter system 1200 includes an outer sheath 1202 for storing thestent 208 in collapsed form, a flange 1216 to pull back the outer sheath1202 and a sleeve retention wire mechanism 1224 for releasing a sleeveretention wire 1210 from the proximal end of the flexible sleeve 202after the stent has been released from the outer sheath 1202.

As described in conjunction with FIG. 2, the distal portion of thegastrointestinal implant device includes a flexible sleeve 202 which cannegotiate the duodenum and the jejunum. A sleeve retention wire 1210travels through a second inner lumen and exits the second inner lumen tosecure the distal end of the sleeve 202 to an inner sheath 1226. Thesleeve retention wire 1210 is coupled to the sleeve retention wirerelease mechanism 1224 for releasing the sleeve retention wire 1210after the gastrointestinal implant device has been positioned in thepyloric section of the stomach. The release mechanism 1224 will bedescribed later in conjunction with FIG. 16B.

The sleeve 202 is secured temporarily outside the inner sheath 1226allowing for proper positioning of the gastrointestinal implant deviceand then for release. As shown, the sleeve 202 is secured by the sleeveretention wire 1210 using a dead-bolt mechanism 1206. Non-stick coatingssuch as Teflon on the sleeve retention wire 1210 are preferred to makerelease easier to accommodate tortuous anatomical pathways. The sleeveretention wire 1210 extends through the second inner lumen from therelease mechanism 1224 of the catheter system 1200 to the dead-boltmechanism 1206. The dead-bolt mechanism 1206 is described later inconjunction with FIG. 14A. The sleeve retention wire 1210 holds thesleeve in position. The distal end of the folded sleeve is released bythe release mechanism 1224 by pulling the sleeve retention wire 1210backward from the proximal end 1208 of the catheter.

As described in conjunction with FIG. 2, the proximal portion of thegastrointestinal device includes a covered stent. The covered stent doesnot enter the duodenum and thus is stiffer than the sleeve because itremains in the pylorus of the stomach. The stent in the gastrointestinalimplant device is collapsed and stored in the outer lumen within theouter sheath 1202 between the flange 1216 and the proximal end 1208 ofthe outer sheath 1202. The stent is supported in a collapsed form by theouter sheath 1202. The catheter 1200 is inserted into the digestivesystem through the esophagus to the pyloric section of the stomach. Theproximal end of the outer sheath 1202 is positioned in the stomach, inthe pylorus through the use of positioning ring 1240. After the outersheath 1202 has been positioned, the stent is retracted from the outerlumen of the catheter by pulling flange 1216 toward the proximal end ofthe catheter system 1200. Upon release, the stent self-expands by itsown elastic restoring force to engage the anchor portion with thestomach muscle at the pyloric section of the stomach.

FIG. 13 is a cross-sectional view of the inner shaft 1226 taken alongline E-E of FIG. 12. The sleeve retention wire 1210 passes through asecond inner lumen 1314 in the inner sheath 1226. The sleeve retentionwire 1210 exits the second inner lumen 1314 and is threaded throughfolds of the sleeve 202 at 1302 in FIG. 14A. The sleeve retention wire1210 re-enters the second inner lumen 1314 at 1302 (FIG. 14A). Theguidewire 1212 passes through the first inner lumen 1310.

FIG. 14A is an expanded perspective view of the dead-bolt mechanism 1206shown in FIG. 12. The sleeve 202 has been folded for delivery. Thesleeve is wrapped around the inner sheath 1226 and bunched above theinner sheath 1226. The sleeve is held in folded position around theinner sheath 1226 by threading the sleeve retention wire 1210 throughthe folds of the sleeve 202. The sleeve retention wire 1210 exits thesecond inner lumen 1314 through an opening 1304 and pierces throughfolds of the sleeve 202 at 1304. Threading the sleeve retention wire1210 through the folds of the sleeve 202 results in a plurality of smallholes at the distal end of the sleeve 202. The holes are reinforced withsilicone or urethane to avoid tears in the material. The sleeveretention wire 1210 re-enters the second inner lumen through a secondhole 1302 and advances a sufficient distance within the second innerlumen toward the distal end of the second inner lumen to resist pullingout of the second inner lumen.

FIG. 14B is a sectional view of the dead-bolt mechanism 1206 shown inFIG. 14A illustrating the sleeve retention wire 1210 threaded throughthe sleeve. The sleeve retention wire 1210 exits the second inner lumenat 1306 and pierces through folds in the sleeve 202 at 104. The sleeveretention wire 1210 re-enters the second inner lumen at 1302.

FIG. 15 is a sectional view of a portion of the catheter system shown inFIG. 12 illustrating the collapsed stent 208 stored inside the outersheath 1202. The stent 208 is pre-compressed and held in a collapsedform inside the outer sheath 1202 of the catheter. The outer sheath 1202is pulled back by the flange 1216 toward the proximal end of thecatheter system 1200 to release the self-expanding stent 208. The stentradially expands under its own elastic restoring force. The guidewire1212 is directed through the first inner lumen and the sleeve retentionwire 1210 is directed through the second inner lumen in the inner sheath1226. The inner sheath includes a first lumen through which theguidewire passes and a second lumen through which the sleeve retentionwire passes.

FIGS. 16A-C illustrate a method for delivery of the gastrointestinalimplant device. FIG. 16A is a plan view of the catheter systemillustrating the collapsed stent stored inside the outer sheath 1202 ofthe gastrointestinal implant device. As described in conjunction withFIG. 12, the stent 202 is stored inside the outer sheath and the distalend of the sleeve 202 is secured outside the inner sheath 1226 by asleeve retention wire 1210.

FIG. 16B is a plan view of the catheter system illustrating thegastrointestinal implant device after release of the stent from theouter sheath. The flange 1216 has been pulled back toward the proximalend of the catheter system 1200 to pull back the outer sheath 1202 fromthe stent and the stent 208 has self-expanded. The sleeve retention wire1210 holds the distal end of the sleeve 202.

Once in place, the sleeve retention wire 1210 can be removed. Asdescribed previously in conjunction with FIG. 12, the sleeve retention1210 is coupled to locking mechanism 1224. Handle 1600 in the lockingmechanism 1224 acts as a pivot device to pull the sleeve retention wire1210 from the dead-bolt mechanism 1206. The distal end of thegastrointestinal implant device is released by moving handle 1600 in aclockwise direction 1604. As the handle 1600 is moved in direction 1604,the sleeve retention wire 1210 threaded through the folds of the sleeveis pulled back through the second inner lumen 1314 and disengages fromthe sleeve at the distal end of the gastrointestinal implant device. Thesleeve retention wire 1206 extends from the distal end of thegastrointestinal implant device through the second inner lumen 1314. Thewire is connected to the handle 1600 at the proximal end of thecatheter.

FIG. 16C is a plan view of the catheter system illustrating the expandedgastrointestinal implant device after the sleeve retention wire has beenreleased. The handle 1600 has been moved in a clockwise direction andthe sleeve retention wire 1210 pulled back through the second innerlumen 1314 to release the distal end of the sleeve 202.

FIG. 17 is a perspective view of another embodiment of the cathetersystem shown in FIG. 16. The catheter includes a ball 1800 coupled tothe distal end 1222 of the inner sheath 1226 for guiding the catheterthrough the alimentary canal to the pyloric portion of the stomach. Theball 1800 is small enough so that it can be pulled back through thegastrointestinal implant device after the gastrointestinal device hasbeen delivered, the stent expanded and the sleeve retention wire 1210has been released. The sleeve is shown uniformly folded. However, thesleeve may not necessarily be uniformly folded.

FIG. 18 is a cross-section of an everting catheter system 1900 fordelivery of a longer flexible sleeve. The gastrointestinal implantdevice 200 is shown with the stent sleeve anchor 1901 and the attachedsleeve 1902 shown as delivered into the anatomy. The delivery catheterpreviously described is then removed. A balloon catheter 1906 isintroduced into the stent sleeve anchor 1901 and the balloon 1908inflated to seal the lumen of the stent 1901. The sleeve 1902 is foldedinside itself and an elastic band 1912 is used to seal the end of thesleeve. Fluid is then injected through the balloon catheter shaft 1906into the sleeve lumen 1910, filling the lumen and pressurizing it. Thepressure of the fluid is used to push the inner sleeve distally towards1904. When the sleeve 1902 has fully deployed distally, the elastic band1912 falls off of the closed end of the sleeve 1902 and passes distallyin the intestine until it is excreted. This mechanism permits deploymentof a sleeve that is double the length of the delivered device. This maybe needed as it is difficult to access the distal parts of the intestinewith guidewires. This everting catheter system enables delivery oflonger sleeves than are possible using only the delivery catheterdescribed in conjunction with FIG. 12.

FIG. 19 is a perspective view of a retrieval device 2000 for removingthe gastrointestinal implant device 200 from the digestive tract. Asalready described, the exterior surface of the stent 208 is covered witha material that prevents cellular in-growth allowing the stent 208 to beeasily removed. The retrieval device 2000 includes an inner sheath 2004and an outer sheath 2006. A plurality of fingers 2002 extend from theproximal end of the inner sheath 2004. The fingers 2002 engage theexterior surface of the gastrointestinal device. As the inner sheath2004 is moved down over the fingers, the fingers 2002 pull radiallyinward to reduce the proximal stent diameter and pull the collapseddevice into the outer sheath 2006.

FIG. 20 is a perspective view of the retrieval device 2000 engaged withthe stent 208. The fingers 2002 of the retrieval device are positionedaround the stent 208. As the inner sheath 2004 is pushed over thefingers 2002, the fingers pull radially inward on the proximal end ofthe stent 208 and the proximal end of the stent 208 is collapsed. Afterthe stent 208 has been collapsed sufficiently such that the proximalstent diameter is less than the diameter of the outer sheath 2006, thestent is drawn into the outer sheath 2006. The entire gastrointestinalimplant device can then easily be removed from the patient by pullingretrieval device 2000 through the stomach and the esophagus.

FIG. 21 is a perspective view of another embodiment of agastrointestinal implant device 2200. The gastrointestinal implantdevice 2200 includes a sleeve 202 and an anchoring ring 2204. The distalend of the anchoring ring 2204 is bonded to the proximal end of thesleeve 202. A plurality of eyelets 2206 are distributed around thecircumference of the proximal end of the ring for anchoring the deviceto the pyloric muscle using anchors shown in FIG. 24. The anchoring ring2204 is made from a flexible material such as silicone allowing the ring2204 to be collapsed for endoscopic insertion and removal.

The anchoring ring 2204 does not hold the pylorus open. However, in analternate embodiment, the anchoring ring 2204 can be bonded to a stentwith sufficient length and diameter to hold the pylorus open asdescribed in conjunction with FIG. 2. The anchoring ring 2204 anchorsthe device and the stent holds the pylorus open.

FIG. 22 is a perspective view of the anchoring ring 2204 shown in FIG.21 in the expanded position. The sleeve is bonded to the outer surface2300 of the proximal end of the anchoring ring whose diameter is 0.8″ orabout the same as the diameter of the sleeve. The anchoring ring 2204includes at least four eyelets to anchor the device in place. The outermost diameter of the ring is about one inch. In an alternate embodimentthere can be more than four eyelets.

FIG. 23 is a perspective view of the anchoring ring 2204 shown in FIG.21 in a collapsed position for insertion and removal. The circular ring2204 shown in FIG. 21 has been compressed to an oval shape allowing theanchoring ring to be inserted into the lumen of a catheter for delivery.

FIG. 24 is a perspective view of an anchor 2500 for anchoring thecollapsible ring shown in FIG. 23 to the muscular tissue of the pyloricorifice. The anchor 2500 includes an anchor pin 2504 coupled to a secondpin 2506 by a flexible shaft 2502. The anchor pin 2504 includes a shapedbarb 2508 for locking the anchor 2500 into the tissue. The anchor 2500is delivered after the collapsible ring has been positioned in thepyloric orifice. The anchor is guided so that the anchor pin 2504 isdirected through a respective eyelet with the barbed portion of theanchor pin 2504 guided toward the tissue. After the barb 2508 has beenlocked into the tissue, the second pin 2506 sits inside thegastrointestinal implant device while the barbed portion 2508 of theanchor pin 2504 sits inside the pylorus muscle tissue. For removal ofthe gastrointestinal implant device from the body, the flexible shaft2502 of the anchor 2500 is cut.

FIG. 25A is a perspective view of a delivery system 2600 for deliveringthe anchor 2500 after the gastrointestinal implant device has beenplaced in the pyloric orifice. The anchor 2500 is loaded in the distalend of a catheter having a single lumen tube 2600. The hollow, distalend of the delivery device is a sharp needle made to penetrate thepylorus muscle. In an alternate embodiment, the distal end of thedelivery device can be formed in an arc to improve access to the eyeletsthrough an endoscopic approach. The catheter 2600 includes a pusher 2604for releasing the anchor 2500. The pusher 2504 is moved in alongitudinal direction 2602 to release the anchor 2500 from the lumen.

FIG. 25B is a plan view of the delivery system 2600 shown in FIG. 25A.FIG. 25C is a cross-sectional view of the distal end of the catheter2600 as taken along line B-B of FIG. 25B. As described in conjunctionwith FIG. 24, the anchor 2500 includes pins 2504, 2506 coupled by aflexible shaft 2502. The anchor 2500 is loaded in the lumen at thedistal end of the catheter 2600. The anchor pin 2504 is placed in thedistal end of the tube 2600 and the second pin 2506 in the proximal end.The barb 2508 on the anchor pin 2504 is pointed toward the proximal endof the tube 2506 to engage with the tissue upon release in the muscletissue. The catheter is advanced to the center of the ring positioned inthe pyloric orifice. The sharp end 2510 is then pushed through an eyeletand into the muscle tissue. The pusher 2506 is pushed in longitudinaldirection 2602 to release the distal anchor 2506. Once the distal anchoris released, the delivery system is pulled back, dragging the proximalpart of the anchor out of the delivery device with the flexible shaftgoing through the eyelet, and the proximal anchor portion resting on theinside of the device. In the embodiment of the ring shown in FIG. 22,four anchors 2506 are delivered to anchor the gastrointestinal implantdevice through the four eyelets.

FIG. 25D is an isometric view illustrating the sharp end 2510 of theneedle inserted through an eyelet 2206 for delivery of the anchor 2500to the tissue 2512. The distal end of the catheter is formed in an arc2520 to improve access the eyelets 2206. The sharp end 2510 of thecatheter is inserted through the eyelet 2206 into the tissue 2516. Theanchor pin 2504 of the anchor has been pushed out from the lumen intothe tissue 2512.

FIG. 25E is an isometric view illustrating the barb 2508 engaging thetissue 2512 after delivery. The catheter has been removed from theeyelet 2206 leaving the anchor pin 2504 engaging the tissue 2516.

FIGS. 26A-E illustrate an alternative embodiment of a locking mechanismfor holding the distal end of the sleeve 202 in position during deliveryof the gastrointestinal implant device. The snare wire 2650 is passedthrough one of the lumens of the catheter to the distal end. At thedistal end, the end of the snare wire 2650 is looped back and attachedto or anchored inside the catheter. The folds of the sleeve 202 areadvanced through this snare loop. The snare handle 2664 pulls andreleases the snare wire 2656 to lock and release the distal end of thesleeve 202. The delivery system includes a pull tap 2666 for releasing adrawstring holding the stent in a collapsed position.

FIG. 26B is cross-sectional view taken along line C-C of FIG. 26Athrough the inner sheath 2650. The inner sheath has two lumens 2654,2656 and has a diameter of about 0.078 inches. The first inner lumen2564 is for passing a guidewire through the inner sheath and is about0.04 inches in diameter. The second inner lumen 2656 is for passing thesnare wire through the inner sheath is about 0.02 inches in diameter.The end of the snare wire 2658 is anchored inside the inner sheath.

FIG. 26C is a cross-sectional view taken along line DD of FIG. 26Athrough the outer sheath 2600 showing the inner sheath within the outersheath. The outer sheath has an inner diameter of about 0.1 inches andan outer diameter of about 0.143 inches. The open space inside the outersheath can be used for passing a drawstring through the outer sheath.

FIG. 26D is a cross-sectional view through the distal portion of thecatheter showing the snare capturing the distal end of the sleeve. Thedistal end of the sleeve 202 is captured by the snare wire 2656 bypulling the distal end of the sleeve through a loop formed by the snarewire 2656.

FIG. 26E is a sectional view through the distal portion of the cathetershowing the snare locking mechanism. The distal end of the sleeve islocked by pulling the snare wire 2656 in a longitudinal direction 2664toward the proximal end of the delivery system to capture the sleevefolds against the inner shaft. After the gastrointestinal implant deviceis properly positioned in the body, the snare wire is advanced in alongitudinal direction 2662 toward the distal end of the deliverysystem. This opens the snare wire 2656 and releases the sleeve 202.

FIG. 27 is a perspective view of the distal portion of thegastrointestinal implant device including texturing 2700. Texturing ofthe distal end of the sleeve can be added to ensure that the actions ofperistalsis do not advance the sleeve proximally, towards the stomach,but keep the sleeve pulled taught in the intestine. At the distal end ofthe sleeve, texturing 2700 is added with a directional aspect to it. Thetexturing 2700 can be molded into the sleeve material or added byadhesive or thermal bonding methods. The texturing material includesfibril shapes that are directed proximally so that any peristaltic wavesthat travel proximally will have less force on the sleeve than distalperistaltic waves.

The gastrointestinal implant device offers a new alternative where othermeans of weight loss and efforts at behavior modification have failed.Because the gastrointestinal implant device is endoscopicallyintroduced, there is a reduced risk at insertion compared to surgery.The procedure is also completely reversible, making this approach theideal solution for patients who are desperate to reverse behavioralpatterns that have led to weight gain.

When inserted in the body, the gastrointestinal implant device mimicsthe duodenal bypass of the Roux-en-Y procedure. The implanted devicereduces caloric absorption by delaying enzyme mixing with food andprovides the feedback produced by the Roux-en-Y procedure by producingdumping syndrome when high sugar meals are ingested. Rapid stomachemptying is encouraged by inserting a stent in the pylorus to hold thepylorus open and all food bypasses the duodenum and passes rapidly intothe jejunum. The implant device is an improvement on the Roux-en-Yprocedure because it is minimally invasive and reversible. In thetreatment of the super-obese where aggressive weight loss is notachieved, the length of the implant device below the stent can befurther increased to drive the patient close to the point ofmalabsorption.

Placement of the gastrointestinal implant device effectively providesthat ingested food does not digest in a normal manner and the guthormones that are normally triggered are modified. These hormones resultin several physiology changes that impact hunger and digestion. Guthormones include peptide YY (PYY), cholecystokinin (CCK) and ghrelin.

As under digested food enters the ileum or distal part of the smallintestine, a hormone called peptide YY or PYY is released. This hormonehas been shown to have a direct effect on appetite, reducing it whenreleased. Undigested food in the ileum indicates that too much food hasbeen ingested. Thus, dependent on the length of the sleeve, thegastrointestinal device can promote deposition of undigested orpartially digested food to the distal bowel. Therefore, the placement ofa sleeve in the intestine promotes the delivery of undigested food tothe ileum, which in turn promotes the release of PYY and reducesappetite in humans.

The hormone cholecystokinin (CCK) is released when food contacts theduodenum. CCK triggers the release of bile from the gallbladder.Therefore, placing a sleeve in the duodenum reduces the release of CCKand thus reduces bile output resulting in reduction in the digestion offood.

Some ghrelin is released when food contacts the duodenum. Ghrelin hasbeen shown to be a factor in the control of appetite. This device willreduce ghrelin output and thereby reduce appetite due to the bypass ofthe duodenum.

Type 2 diabetes is a disease of obesity that occurs when patients cannotadequately use the insulin they produce. Usually, it is not that thepatient cannot make enough insulin, but rather that the patient's bodycannot effectively use the insulin produced. A particularly dangerousresult of type 2 diabetes is that blood sugar spikes after a meal. Thisis called post-prandial hyperglycemia. This spike in blood glucosecauses cardiovascular and microvascular damage. One class of drugs usedto control post-prandial hyperglycemia is the alpha-glucosidaseinhibitors. These work by reducing the breakdown and absorption ofcarbohydrates to sugars. The sleeve has a similar function because itreduces bile and delays the breakdown and absorption of thecarbohydrates, which are normally readily absorbed in the duodenum, butare less likely to be absorbed in the jejunum and ileum. Therefore, type2 diabetes can be controlled by placing a sleeve in the proximalintestine to delay the digestion of carbohydrates which reducespost-prandial hyperglycemia.

The gastrointestinal implant device can be used to reduce Type 2diabetes symptoms by bypassing the duodenum. Following gastric bypasssurgery, patients commonly experience complete reversal of Type 2diabetes. While the exact mechanism of this remarkable effect is notunderstood, the clinical result is reported in a high percentage ofcases. Reversal of Type 2 diabetes after gastric bypass is described in“Potential of Surgery for Curing Type 2 Diabetes Mellitus” by Rubino etal. incorporated herein by reference in its entirety. Since thegastrointestinal implant device provides equivalent blockage of duodenalprocesses, a similar effect is elicited but without the trauma ofsurgery. In patients who are not obese but suffer Type 2 diabetes, amodified gastrointestinal implant device is inserted. Thisgastrointestinal implant device provides the necessary effect to hinderpancreatic processes and receptors without blocking absorption.

In the embodiment of the gastrointestinal implant device for treatingdiabetes, the length of the stent may be selected to allow the pylorusto operate normally. The length of the sleeve may be reduced to mimicthe duodenum bypass. The sleeve extends to just below the ligament ofTreitz but does not extend further into the jejunum, thus allowingabsorption to occur in the jejunum.

The gastrointestinal implant device can be placed temporarily in thestomach and duodenum to allow tissues to heal. For example, the sleevecan be placed temporarily to promote healing of ulcers in the stomachand duodenum. Ulcers are lesions that form in tissues of the stomach andduodenum. If they bleed, they are typically cauterized withelectrosurgery. For ulcers to heal, they must be protected from theacidic environment. Placement of a sleeve for a short time period, forexample, for one to two weeks, promotes healing of ulcers in the stomachand duodenum by eliminating the acidic environment and allows thetissues to heal.

Intestinal anastomoses are performed to remove sections of diseasedbowel. The stapled or sewn connection is prone to leakage until itheals. The placement of the gastrointestinal implant device temporarilyin the bowel can be used to promote healing of small bowel anastomosesby protecting the area from chyme and minimizing leaks.

The gastrointestinal implant device can be used to deliver drugs,hormones and other active agents directly to the intestine. To deliverthe agents, the sleeve is either coated or impregnated with the agents.

The two most common intestinal bowel diseases are Crohn's disease andulcerative colitis. Crohn's disease may occur in any part of thedigestive tract. Although the exact cause of the disease is unknown, itappears to be an abnormal immune response in the patient, which leads tochronic inflammation of the intestinal lining.

Crohn's disease is treated with drugs intended to reduce inflammation.These include aminosalicylates, corticosteroids, immune modifiers suchas azathioprine and methotrexate and antibiotics including ampicillinand cipro. These drugs have negative effects when given systemically.Since the drug is really only needed locally, smaller amounts of drugcan be used if delivered directly to the tissues.

The intestinal sleeve is coated with polymers that are impregnated withthese drugs. Coatings may include polyurethanes, silicones andhydrophilic polymers like Hydromer. These coatings may be applied to thesleeve material by dipping or spraying techniques. If a porous sleevematerial such as ePTFE is used, the drug filled polymer may be driveninto the pores using internal pressure inside the sleeve. This increasesthe amount of drug that is available.

The sleeve material can also be a polymer that permits the incorporationof the drug directly into the wall. Such polymers include Ethylene VinylAcetate (EVA) and polyurethane. A greater amount of the drug may beincorporated in this case compared to a coating since there is morematerial in the wall than simply in coatings, thereby providing longerrelease times. The drug is compounded into the polymer and then extrudedas is normally done to form the tubing or sheet from which the sleeve ismade.

The sleeve is deployed transesophageally into the duodenum and proximaljejunum. When the sleeve comes in contact with the tissues, the drugs inthe coating are released directly into the tissues. Also, the sleeve mayact to block the contact of the food to the mucosa, thereby reducingirritation caused by the chyme. Once the drug has fully eluted from thematerial, the sleeve is removed and a new one is placed.

The control of appetite in the human is a complex function of hormonalinteractions. Several hormones have been implicated in its controlincluding Ghrelin, PeptideYY, Leptin, Glucagon-Like Peptide-1 (GLP-1),Cholecystokinin (CCK), insulin and others. These hormones are eitherreleased or suppressed by the presence of food in the duodenum. Forexample, PYY acts as an anti-hunger hormone as injections of PYY havebeen shown to decrease food intake in both rats and humans and decreasesin leptin have been shown to stimulate hunger.

Sleeves that are located in the duodenum where many of these hormonesare released may be impregnated with these hormones. When implanted, thehormones elute from the sleeve into the surrounding tissue where theyactivate the various satiety mechanisms.

FIG. 28 is a perspective view of a gastrointestinal implant device withanother embodiment of a collapsible self-expanding anchoring device. Thegastrointestinal implant device 2800 includes a sleeve 202 and ananchoring device for anchoring the gastrointestinal implant device inthe pylorus. The anchoring device includes two rings 2803, 2802 ofdiffering diameters. A portion 2806 has been cut off to show the rings2803, 2802. The rings are made from a metal such as heat treated springsteel. In one embodiment the rings are made from Nitinol.

The rings are spaced apart and are covered by the sleeve 202. The distalend of the proximal ring 2803 is bonded to the proximal end of thesleeve 202. The distal ring 2802 is also bonded to the sleeve distal tothe proximal ring. The rings are spaced apart such that when thegastrointestinal device is positioned in the body, the proximal ring islocated in the stomach and the distal ring is located in the duodenum.

The proximal ring 2803 serves to prevent the device from moving in thedistal direction 2805 into the duodenum. The distal ring 2802 serves toresist motion in the proximal direction 2804. The diameter of each ofthe rings is variable with the diameter of the proximal ring greaterthan the diameter of the distal ring. In one embodiment, the diameter ofthe proximal ring 2803 is about 1.4″ (35.6 mm) and the diameter of thedistal ring 2802 is about 1.0″ (25.4 mm). The diameters of the rings aredependent on the anatomy. The diameter of the proximal ring 2803 isselected to be greater than the pyloric orifice which is typically about1″ in diameter to prevent the ring from being pulled through the pyloricorifice to the intestines. The diameter of the distal ring 2802 isselected so that the ring is less than the diameter of the duodenum. Thedistance between the rings is dependent on the length of the pyloricorifice. This distance is selected so that when the proximal ring 2803is positioned in the stomach, the distal ring 2802 is positioned at thedistal end of the pyloric orifice in the duodenum. The distance betweenthe rings also determines whether the pylorus is held open. If thedistance between the rings is equal to the length of the pylorus, thepylorus is held open. If the distance between the rings is greater thanthe length of the pylorus, the sleeve material between the rings isloose allowing the pylorus to operate normally.

FIG. 29 is a plan view of one of the rings 2803 in the gastrointestinalimplant device shown in FIG. 28. The ring 2803 includes a wire 2906 anda crimp connector 2907. The ends of the wire 2908, 2909 are connectedthrough the crimp connector 2907 to form the ring 2803. The anchoringdevice can be collapsed into a sheath to enable endoscopic delivery.

The wire is made from a Nitinol material and is heat treated to providea super elastic state at a range of temperatures from room temperaturethrough body temperature. The wire 2906 is about 0.020″-0.027″ indiameter. The diameter of the wire is selected to provide sufficientradial stiffness to resist collapse by forces in the body, but to permitcollapse into a delivery device.

FIG. 30 is a perspective view of the anchoring device in thegastrointestinal implant device shown in FIG. 28 in a collapsed positionin a delivery tube 3010 for delivery into the body. The anchoring deviceis delivered to the stomach by folding each of the rings 2803, 2802 in adouble U shape to reduce their diameter and length, so that the ringsfit inside the delivery tube 3010 for endoscopic delivery and to permitdeployment of the rings in a serial manner.

The delivery tube 3010 has a diameter of about 0.394″-0.591″ (10-15 mm)and is about 2 inches in length. The rings 2803, 2804 are folded suchthat they fit inside the delivery tube 3010 and do not exceed theelastic limit of Nitinol. The folding into a double U shape also permitsthe rings 2802, 2803 to be pushed out of the delivery tube 3010 indistal direction 2805 in an orderly manner for delivery into the body.After delivery of the gastrointestinal device, the delivery tube 3010 isremoved from the body through the stomach in proximal direction 2804.

FIG. 31 is a perspective view of the gastrointestinal deviceillustrating the deployment of the distal ring from the delivery tube3010 shown in FIG. 30. As described in conjunction with FIG. 30, therings 2803, 2302 are folded in a double U shape and are loaded intodelivery tube 3010. A piston 3101 and proximal shaft 3102 are moveablewith respect to delivery tube 3010 such that as the delivery tube 3010is pulled in proximal direction 2804, or the shaft 3102 is pushed indistal direction 2805, the distal ring 2803 is first deployed in theduodenum, and then the proximal ring 2802 is deployed proximal in thestomach.

FIG. 32 is a perspective view of the gastrointestinal device after thedeployment of the distal ring 2803 prior to deployment of the proximalring 2802. After deployment, the distal ring 2803 expands under its ownelastic force and is positioned in the duodenum. The portion of thesleeve 202 between the rings is then pulled in proximal direction 2804.As the second proximal ring 2802 is released, it is positioned in thestomach.

FIG. 33 is a perspective view of the gastrointestinal implant deviceshown in FIG. 28 with an alternative embodiment of an anchoring device.The anchoring device includes two nitinol rings 3300, 3302 of differingdiameters where the rings are shaped with stabilizing ears 3304 toprevent the rings from twisting.

Each of the rings 3300, 3302 is fabricated from nitinol wire aspreviously described. Each ring contains loops (stabilizing ears) 3304that protrude beyond the diameter of the ring. These loops 3304 serve toprovide additional anchoring into the tissues and especially to limitrotation of the rings in place. The addition of the loops to each ringpermits reduction of the wire diameter and/or the ring diameter whilemaintaining similar anchoring ability. This also reduces trauma to theanchoring tissues. The number of loops 3304 is variable. There can betwo, three or four loops. In the embodiment shown, each ring has fourloops. As the gastrointestinal device is a removable, tissue in-growthinto the anchoring device is not desired. Therefore, each loop 3304 iscoated with a polymer such as polyurethane in a dipping process to fullycover the openings.

FIG. 34 is a plan view of the gastrointestinal implant device shown inFIG. 33. The loops on each of the rings protrude through the exteriorsurface of the sleeve to push against the tissue to anchor thegastrointestinal implant device in the pyloric region of the stomach.The non-loop portions of each of the rings are encapsulated by thesleeve.

FIG. 35 is a perspective view of another embodiment of one of theanchoring rings shown in FIG. 28. In the embodiment shown, a ring 3500is formed from multiple wires. In this case, two wire loops 3502, 3504are loosely intertwined to form a single anchoring ring 3500. By formingthe ring from multiple wires, the diameter of the wire can be reduced.Therefore, the rings can be folded into a smaller delivery device andstill maintain the same the radial force on the tissue as the singlewire embodiment to hold the ring in place when deployed. Additionalwires can be used to further reduce the diameter of the wires. Wire 3502contains loops 3506 that protrude beyond the diameter of the ring 3500to provide additional anchoring into the tissues.

FIG. 36 is a perspective view of a gastrointestinal implant device withyet another embodiment of an anchor. The device includes two nitinolrings of differing diameters that are linked together with connectingrods 3600 to stabilize the rings 2803, 2802. The connecting rods 3660stabilize the anchor by limiting motion of the rings.

The anchor is formed by proximal ring 2803 and distal ring 2802 looselyconnected by at least one connecting bar 3600. There are loops 3602,3604 at the end of each connecting bar 3600, each loop 3602, 3604engages a respective one of the rings 2803 and 2802. The sleeve 202encapsulates the entire assembly.

FIG. 37 is a perspective view of the anchor shown in FIG. 36 with thesleeve 202 removed. There are four interconnecting bars 3600 spacedapart from each other around the diameter of the rings 2803, 2802. Theinterconnecting bars 3600 serve multiple functions. First, when theanchor is in position in the body with the proximal ring 2803 in thestomach and the distal ring 2802 in the duodenum, the interconnectingbars 3600 serve to stent open the pylorus. Second, the interconnectingbars 3600 serve to stabilize each of the rings 2803, 2802 and limit thetwisting or translational motion of the rings with respect to eachother.

FIG. 38 is a perspective view of the anchor shown in FIG. 37 in acollapsed position in a delivery tube 3010 for delivery into the body.The rings 2803, 2804 connected by connecting bars 3600 are folded in adouble U shape and placed inside the delivery tube 3010. As described inconjunction with FIG. 30, after delivery of the gastrointestinal device,the delivery tube 3010 is removed from the body through the stomach inproximal direction 2804.

FIG. 39 is a perspective view of the anchor shown in FIG. 37illustrating the deployment of the distal ring 2803 from the deliverytube 3010 shown in FIG. 38. As described in conjunction with FIG. 31,the distal ring 2803 is first deployed distal to the pylorus in theduodenum, and then the proximal ring 2802 is deployed proximal to thepylorus in the stomach.

FIG. 40A is a plan view of the gastrointestinal device shown in FIG. 38with additional anti-rotation and locking features. The connecting rods3600 are further formed with loop extensions 4000. The loop extensions4000 on each connecting rod 3600 are angled towards each other. Theseloop extensions 4000 press against the muscle of the pylorus to anchorthe gastrointestinal implant device in the pylorus portion of thestomach and serve to prevent any linear motion of the device. Rotationof the device is also reduced. The loop extensions 4000 are coated withpolyurethane to prevent tissue in growth.

FIG. 40B is a perspective view of the anchor shown in FIG. 40A withoutthe sleeve. The loop extensions 4000 on a connecting bar 3600 are angledtowards each other to prevent linear motion. The loop extensions on theproximal end of the connecting bar 3600 are angled in a distal directionand the loop extensions on the distal end of the connecting bar areangled in a proximal direction.

FIG. 41 is a plan view of an alternative embodiment of agastrointestinal implant device shown in FIG. 28. The gastrointestinaldevice includes two nitinol rings 2802, 2803 of differing diameters asdescribed in conjunction with the embodiment described in conjunctionwith FIG. 28. The gastrointestinal implant device has sleeve material202 on the inside and the sleeve material and rings are coated with apolymer such as polyurethane 4100 on the outside.

FIG. 42A is a perspective view of a portion of a low profile cathetersystem 4250 for delivery of a gastrointestinal implant device. The lowprofile catheter has a detachable generally spherical shaped element4218 coupled to the distal end of an inner shaft 4200 to aid thedelivery of the catheter through the alimentary canal to the intestines.After the gastrointestinal implant device has been delivered, thespherical shaped element (ball) 4218 is detached and the zero profilecatheter is removed through the gastrointestinal implant device. Thenormal peristalsis of the bowel is used to move the released ballthrough the intestines.

The catheter system 4250 includes an outer sheath 4222 for storing thecollapsible anchor portion of the gastrointestinal implant device incollapsed form. Collapsible anchoring devices have already beendescribed in conjunction with FIGS. 7, 23 and 30. The sleeve 202 issecured temporarily outside an inner sheath 4200 allowing for properpositioning of the gastrointestinal implant device and then for release.

FIG. 42B is a cross-sectional view of the inner shaft 4200 of thecatheter system as taken along line 42B-42B of FIG. 42A. In oneembodiment, the inner shaft 4200 is a three-lumen extrusion of Pebax7233 with an outer diameter of 0.080″ and round inner lumens 4202, 4204,4206 having respective diameters of 0.040″, 0.020″ and 0.020″. Thismaterial is selected to maintain a low profile, a small minimum bendradius; that is less than 0.5″ without kinking, good column strengthwhen fortified with an inner guide wire stylet, and a low coefficient offriction in a material with good thermoplastic and bonding properties.

A first lumen 4202 is used to pass a guide wire or mandrel 4226 throughthe catheter shaft to increase the rigidity of the catheter shaft duringintroduction of the catheter into the intestines. The first lumen 4202is also used to inject fluid to lift the sleeve material 202 away fromthe inner shaft 4200 after the gastrointestinal device has beendelivered to the intestine. A second lumen 4204 is used to pass a sleeveretention wire 4208 to the distal end of the gastrointestinal implantdevice. The sleeve retention wire is used to hold the distal end of thesleeve 202 to the outside of the inner shaft 4200. A third lumen 4206 isused to inject fluid at the tip of the catheter to lift the distal endof the sleeve 202 off the inner shaft 4200 prior to removal of thecatheter system 4250 from the body.

Returning to FIG. 42A, the guide wire 4226 is passed through fitting4210 connected to the first lumen 4202. The sleeve 202 is locatedconcentrically over the catheter inner shaft 4200. It is held at itsdistal end to the inner shaft 4200 with the sleeve retention wire 4208.The sleeve retention wire 4208 holds the sleeve 202 in place duringdelivery.

Proximal fitting 4220 is connected to the second lumen and proximalfitting 4212 is connected to the third lumen 4206. During delivery ofthe gastrointestinal implant device, the first lumen 4202 is filled witha 0.035″ Teflon coated guide wire 4226 that provides column strength forthe appropriate amount of pushability without compromising theflexibility of the catheter inner shaft 4200. A 0.015″ diameterTeflon-coated steel wire is placed in the second lumen 4204 to serve asthe distal sleeve retention wire. The second lumen 4204 has 2 skiveholes 4214, 4216 near the distal end of the catheter shaft 4200. Thedistal sleeve retention wire 4208 exits the second lumen 4204 through aproximal skive hole 4214 feeds through the sleeve material 202, which iswrapped tightly around the distal outer diameter of the catheter shaft,and re-enters the second lumen 4204 through a distal skive hole 4216.This creates a dead bolt style lock holding the sleeve 202 to the shaft4200 until ready to be released similar to the dead bolt style lockdescribed in conjunction with the two lumen catheter shaft shown inFIGS. 14A and 14B.

The distal end of the shaft terminates with a spherical shaped element4218 that is either solid, or inflatable to form an atraumatic tip. Inthe embodiment shown, the spherical shaped element is a solid ball,similar to the ball described in conjunction with FIG. 17. In theembodiment shown, the diameter of the ball is about 0.5″ (12.7 mm),however the range of diameters is about 0.25″ (6.4 mm) to about 0.75″(19.2 mm). An embodiment of an inflatable spherical shaped element isdescribed later in conjunction with FIGS. 50A-50B. The ball 4218 at theend of the catheter shaft is held onto the shaft 4200 with the sleeveretention wire 4208 maintaining tension on the ball 4302 which will bedescribed later in conjunction with FIG. 46.

The collapsed anchor assembly is located in outer sheath 4222. The ball4218 at the end of the catheter is released to withdraw the catheter.The release mechanism pulls the sleeve retention wire to release theball end and release the end of the sleeve. The anchor assembly is thenreleased from the outer sheath as previously described

The catheter can be used any time access to the intestinal tract isdesired. For example, the catheter can be used to pass an endoscope intothe intestine. This catheter device can be used to rapidly run theintestines, place a guide wire and then use the placed guide wire as atrack for an endoscope.

FIGS. 43-45 illustrate the steps for delivery of the gastrointestinalimplant device using the low profile catheter described in conjunctionwith FIGS. 42A-42B. FIG. 43 is a sectional view of a portion of thedigestive tract in a body illustrating the position of agastroscope/guide tube assembly.

The small bowel is accessed endoscopically by passing a semi-rigid tubeinto the stomach and into the pylorus and proximal duodenum, inflatingthe bowel with a fluid, preferably water, and then passing a thin,flexible catheter with a large, atraumatic ball tip through the bowel.

A guide tube 4300 is placed over the end of a gastroscope 4302. Theguide tube/gastroscope assembly is then placed through the patient'smouth, down the esophagus and into the stomach 102. The assembly is thenpassed into the pylorus 108 and the duodenum 104.

The guide tube 4300 has an inner diameter of approximately 0.63″ (16 mm)and an outer diameter of approximately 0.70″ (18 mm). It isapproximately 30″ (76.2 cm) in length and is made of a flexible polymersuch as urethane with a flat wire wrap to provide kink resistance andpushability. The distal end of the guide tube 4300 can have a short,flexible end to minimize trauma to the pylorus 108.

Once in place, fluid is introduced through the channel of thegastroscope 4302 to inflate the intestine distally. Saline or water arepreferred but air or carbon dioxide (CO₂) can also be used. About500-1000 cc of fluid is introduced for delivery of a 4′ length ofsleeve. Shorter sleeves require less fluid because the length ofintestine to distend is less. After the fluid is introduced, thegastroscope is removed from the guide tube.

If desired, the gastroscope 4302 can be removed from the guide tube 4300and a balloon catheter can be introduced to deliver the fluid. Theballoon catheter is delivered to the pylorus and inflated to roughly0.394″-0.591″(10-15 mm) to seal the intestine. A balloon catheter hasalready been described in conjunction with FIG. 18.

FIG. 44 is a sectional view of a portion of the digestive tract in abody illustrating the distal portion of the catheter assembly extendingfrom the distal portion of the guide tube 4300. The catheter assembly4250 is advanced through the guide tube 4300 after the gastroscope 4302has been removed from the guide tube. The ball 4218 at the end of thecatheter assembly 4250 provides an atraumatic, leading tip to thecatheter such that the catheter follows the contour of the intestines.

FIG. 45 is a sectional view of a portion of the digestive tract in abody after the gastroinstestinal implant device of FIG. 28 has beendelivered. The anchor of the gastrointestinal implant device is locatedinside the delivery tube 4222, which is located in the pylorus 108. Amarker on the proximal end of the catheter 4200 aligns with acorresponding marker on the guide tube 4300 when the catheter is fullyinserted. Once the gastrointestinal device is in place, the sleeveretention wire 4208 in the catheter 4302 which holds the sleeve 202 inplace and also holds the ball 4218 to the distal tip of the catheter canbe removed as discussed in conjunction with the catheter system shown inFIGS. 16A-16C. As the sleeve retention wire is pulled back in a distaldirection, both the ball 4400 and the distal end of the sleeve 4500 arereleased. Fluid is then introduced through the third lumen 4206 in thecatheter to open the sleeve 202 and expand the sleeve away from thecatheter shaft 4200. Water or saline are preferred fluids although airor CO₂ can be used. Approximately 100-200 cc is injected. The fluidexits the catheter at a mid point skive hole 4502 and travels in both adistal and proximal direction. Approximately 20 cc of fluid is theninjected through the second lumen 4204 and exits the distal skive hole4216. This fluid lifts the distal end of the sleeve 202 off the innercatheter shaft 4200.

The guide tube 4300 is then removed and the gastroscope re-introducedinto the stomach to view the pylorus 108. The proximal anchor is thendeployed by pulling back on the delivery tube 4222, which is connectedto the proximal end of the catheter. After the anchor is deployed asdescribed in conjunction with FIGS. 31 and 32, the catheter system 4250is withdrawn from the patient. The catheter 4302 has no edges that couldcatch on the sleeve 202 as it is pulled back through the stomach 102 andthe esophagus because the ball is left behind. This zero profilecatheter design is important since it is typically very difficult towithdraw devices from the gastro-intestinal tract while leavingcatheters or other devices behind.

A method for accessing the small bowel by passing a catheter through themouth has been described in conjunction with FIGS. 43-45. The lowprofile catheter can also be used for accessing the small bowel throughan incision in the stomach. Instead of delivering the catheter throughthe top of the stomach as shown in FIG. 43, the catheter is deliveredthrough the stomach, for example, through an incision at position 4304in FIG. 43. The bowel is filled with a fluid, preferably water, and thenthe thin, flexible catheter with a large, atraumatic ball tip throughthe bowel is passed through the bowel as described in conjunction withFIG. 43-45.

FIGS. 46-48 illustrate embodiments for attaching a releasable sphericalshaped element to the distal end of the catheter. FIG. 46 is a plan viewof the distal end of the catheter system illustrating a releasable balltip mechanism. As discussed in conjunction with the catheter systemshown in FIG. 42, a sleeve retention wire 4208 travels through secondlumen 4204 in the catheter shaft 4200 exits the second lumen 4204through proximal skive hole 4214 and re-enters the second lumen throughdistal skive hole 4216.

The ends of wire 4600 are attached to the ball 4218 and the wire 4600 islooped through sleeve retention wire 4208 to hold the ball 4218 at thedistal end of the inner shaft 4200 of the catheter. The ball 4218 isreleased by pulling back on sleeve retention wire 4208 with fitting 4220(FIG. 42A) until wire 4600 is no longer held by sleeve retention wire4208. The ball 4218 then falls off the distal end of the inner shaft ofthe catheter 4200 and exits the body through normal peristalsis throughthe intestines.

FIG. 47 is a plan view of the distal end of the catheter illustrating analternative embodiment of a releasable ball tip mechanism. The innershaft 4200 fits in recess 4706 in the ball 4218. The sleeve retentionwire 4208 exits the inner shaft 4200 through proximal skive hole 4214,pierces the sleeve 202 and re-enters the inner shaft 4200 through distalproximal skive hole 4216. The distal end of the sleeve retention wire4208 is formed into a coil shape 4700 and sits in a pocket 4702 in theball 4218. The pocket 4702 is connected to the recess 4702 through hole4704, which is of a smaller diameter than the recess 4702 and the pocket4700. The distal end of the sleeve retention wire 4208 is annealed sothat the sleeve retention wire 4208 can be pulled back in a proximaldirection and will straighten out to allow the wire to pass through hole4704.

FIG. 48 is yet another embodiment of a releasable ball tip mechanism.The inner shaft 4200 fits in recess 4706 in the ball 4218. The sleeveretention wire 4208 exits the inner shaft 4200 through proximal skivehole 4214, pierces the sleeve 202 and re-enters the inner shaft 4200through distal proximal skive hole 4216.

The ball 4218 includes two holes 4800, 4802 extending from the recess4706 to the exterior surface of the ball 4218. The distal end of thesleeve retention wire 4208 passes through hole 166 and is looped backinto hole 167. As the sleeve retention wire 4208 is pulled proximally,the wire 4218 is pulled back through hole 4802 and then through hold4800 and the ball 4218 is released from the distal end of the catheter.

FIG. 49 is a cross sectional view of an alternative embodiment of asolid spherical shaped element. A ball 4900 is fabricated in two halves,4902 and 4904. The sleeve retention wire 4006 fits into an S shapedtrack 4908. The S shape of the track 4908 creates sufficient friction tohold the ball on the end of the catheter during delivery of thegastrointestinal implant device. The sleeve retention wire 4600 fitssnugly in the channel 4908 but can be pulled proximally to release thesleeve retention wire 4600 from the ball 4900. The catheter shaft fitsin the recess 4906.

A low profile balloon can be used instead of the ball 4218 at the distalend of the catheter. FIGS. 50A-50B is a plan view of the distal end ofthe catheter shown in FIG. 44 with a low profile balloon. In theembodiment shown, a low profile balloon replaces the ball at the distalend of the catheter shown in FIG. 44. FIG. 50A is a plan view of thedistal end of the catheter with an inflatable spherical shaped element.FIG. 50B is a plan view of the distal end of the catheter after theinflatable spherical shaped element has been inflated;

Referring to FIG. 50A, a silicone or latex sleeve 202 is attached to thedistal end of the catheter shaft 4302. Filling holes 5010 connect withthe inner lumen of the catheter to provide a passage for inflation of aninflatable spherical shaped element (balloon) 5008. The balloon 5008 isattached to the shaft 4302 with a metal band 5000 that has a taperedproximal transition 5002 to minimize edges that could catch on thesleeve 202 after delivery of the sleeve 202. The metal band 5000 isabout 0.003-0.005″ (0.076-0.127 mm) thick. The balloon 5008 can be thinwall molded, tubular polyurethane or silicone. The balloon is storedalong the distal catheter shaft 4302 with the distal end pushed into thelumen of the catheter shaft and attached to the catheter shaft 4302 witha plug 5006 to keep the balloon from expanding beyond the tip of thecatheter.

FIG. 50B illustrates the distal end of the catheter 4302 after theballoon 5002 has been expanded into a spherical shape. The balloon isexpanded by fluid, which flows through the catheter shaft and enters theballoon 5008 through the fluid passage holes from the catheter shaft.The plug 5006 at the end of the catheter shaft ensures that the balloonacts like the ball shown in the embodiment in FIG. 50 by limitingexpansion of the balloon beyond the tip of the catheter and the plugalso provides some lateral strength to the balloon. By replacing theball with a balloon at the distal end of the catheter, the distal tip ismore stable for axial compression. Also, the catheter will not deflectwith side loading.

The further one tries to pass a device into the intestine, the moredifficult it is since friction and tortuosity increase. FIG. 51 is aplan view of an alternative delivery system for delivering agastrointestinal implant device. The delivery system enables delivery ofa long sleeve into the intestine and includes a distal pill with foldedsleeve material inside. Peristalsis carries the pill distal in theintestine, causing the sleeve material to unfurl.

The delivery system is described for delivering the embodiment of thegastrointestinal device described in conjunction with FIG. 28. However,the delivery system is not limited to the delivery of a distal sectionof the sleeve for this embodiment of the gastrointestinal implantdevice. As described in conjunction with FIG. 28, the gastrointestinaldevice includes a proximal ring 2802, a distal ring 2803 and a sleeve202. The proximal section of the sleeve is fully deployed and someamount of the distal section of sleeve 202 is packed into a pill 5100.

The gastrointestinal implant device is delivered as previously describedinto the proximal intestines. Once deployed in the intestines,peristalsis from the natural activity of the intestine pulls the pill5100 distally through the intestine. As the pill is pulled distally, thedistal section of the sleeve 202 pulls out of the pill and deploysstraight in the intestine. Peristalsis pulls the pill through theremainder of the intestines and the pill finally exits the body.

A one-foot length of sleeve material can be packed into a pill withlength of 1″ (25.4 mm) and diameter of 0.47″ (12 mm). Therefore, if oneonly wishes to pass the catheter 2 feet into the intestine for deliveryof the gastrointestinal device, the pill 5100 enables a 3 foot sleeve tobe delivered with the additional 1′ distal section of the 3-foot sleevedelivered in the pill 5100.

FIG. 52 is a plan view of another embodiment of the delivery mechanismshown in FIG. 51. The delivery mechanism enables delivery of a longsleeve into the intestine and includes encapsulated sleeve materialsformed into pill shapes. Each pill dissolves in the body at differentrates enabling the sleeve to be pulled distally by peristalsis as itunfolds once the pill covering dissolves.

The delivery mechanism is shown for delivery of the gastrointestinalimplant device described in conjunction with FIG. 28. The first sectionof the sleeve 202 is fully deployed after the gastrointestinal implantdevice has been delivered into the proximal intestine as previouslydescribed. A plurality of distal sections of the sleeve 202 are coatedto form a plurality of dissolvable pills 5200, 5202, 5204. The coatingsapplied to form each respective pill 5200, 5202, 5204 are made of adissolvable material, with each coating tailored to dissolve atdifferent times depending on the polymer make up and the environment.Each pill 5200, 5202, 5204 is carried distally by peristalsis. Thecoating on the first pill 5200 is selected to dissolve first. After thecoating on the first pill 5200 has dissolved, the second and third pills5202 and 5204 pull the compacted sleeve 202 distally. The coating on thesecond pill 5202 dissolves next, as the third pill 5204 pulls the sleevemore distally. Finally, the coating on the third pill 5204 dissolves andthe sleeve 202 is fully deployed. The plurality of dissolvable pillsenables the ultimate delivery of many feet of sleeve material with thesimpler delivery of only an initial 1-2 foot section of the sleeve intothe proximal intestine. As described in conjunction with the embodimentshown in FIG. 51, a one-foot length of sleeve material can be packedinto a pill with length of 1″ (25.4 mm) and diameter of 0.47″ (12 mm).

A number of biodegradable materials may be used for the coatings on thepills including polyethylene glycols (PEG), polylactic acids (PLA) andpolycaprolactones (PCL). These materials are made in formable resins orin liquids that can be converted to solids through various types ofchemical and photochemical reactions. These materials break down intochemicals that are safe to internal tissues. These resins are madebiodegradable by formulating a base molecule with a hydrolyticallyunstable link within the base chain.

For example, PEG is made biodegradable by incorporating lactic acid intothe base chain. One end of the lactide molecule forms a link that willbreak down rapidly in the presence of water. One means of controllingthe rate of degradation is by varying the number of lactide elementswithin the base chain. The greater the number, the faster the chain willbreak down. Additionally, the percent solids or density of the resultingsolid is varied to alter degradation rates. Denser materials take longerto break down. Also, hydrolytically unstable bonds break down faster inelevated pH environments. Such an environment occurs naturally withinthe small intestines, on the outside of the sleeve where bile andbicarbonates are deposited.

FIGS. 53A-53C illustrate a method for delivering an alternate embodimentof the catheter system 4250 having a central lumen for placement over aguide wire. FIG. 53A is a sectional view of a portion of the digestivetract in a body illustrating an enteroscope 5300 extending through thestomach, through the pylorus 104 to the duodenum 104. A guide wire 5302is then passed through the enteroscope 5300. After the guide wire hasbeen passed through the enteroscope 5300 is removed. FIG. 53B is asectional view of a portion of the digestive tract in a bodyillustrating the guide wire 5302 extending through the stomach 104 andthe duodenum 104 after the enteroscope 5300 has been removed. Thecatheter system follows a guide wire 5302 through the esophagus and thestomach to the pylorus portion 108 of the stomach 102. FIG. 53C is asectional view of a portion of the digestive tract in a bodyillustrating the catheter extending through the stomach 102 and duodenum104 over the guide wire 5300. After the gastrointestinal implant devicehas been delivered, the catheter 4200 is pulled back through thestomach. After the catheter has been removed, the guide wire 5302 ispulled back through the intestines and the stomach 102.

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

What is claimed is:
 1. A delivery apparatus for delivering agastrointestinal device, the apparatus comprising: a gastrointestinaldevice comprising a tube; a shaft extending through the tube, the shaftconfigured to pass through a length of the intestines and to deliver thegastrointestinal device; an atraumatic element, distinct from thegastrointestinal device, distal to and releasably coupled to a distaltip of the shaft; and a release mechanism that releasably engages theatraumatic element to retain the atraumatic element on the distal tip ofthe shaft, the release mechanism comprising a moveable element, theatraumatic element being released from the distal tip of the shaft andthe moveable element by movement of the moveable element, the shaftincluding first and second holes near its distal tip, the moveableelement exiting the shaft via the first hole and re-entering the shaftvia the second hole.
 2. The apparatus according to claim 1, wherein theshaft and gastrointestinal device are disposed within a guide tube, theguide tube configured to guide movement of the shaft andgastrointestinal device.
 3. The apparatus according to claim 2, whereinthe guide tube guides the passage of the shaft and gastrointestinaldevice through a length of the stomach.
 4. The apparatus according toclaim 1, wherein the atraumatic element is remotely releasable.
 5. Theapparatus according to claim 4, wherein the atraumatic element comprisesa ball.
 6. The apparatus according to claim 4, wherein the atraumaticelement is inflatable.
 7. The apparatus according to claim 1, whereinthe atraumatic element is attached to a loop which is held by therelease mechanism.
 8. The apparatus according to claim 1, wherein theatraumatic element is larger in diameter than the shaft.
 9. Theapparatus according to claim 8, wherein the atraumatic element is 0.25inches to 0.75 inches in diameter.
 10. The apparatus according to claim1, wherein the shaft is a catheter having a lumen therein.
 11. Theapparatus according to claim 1, wherein the shaft has a minimum bendradius of less than 0.5 inches without kinking.
 12. The apparatusaccording to claim 1, wherein the moveable element extends along a firstlumen in the shaft and a wire extends along a second lumen in the shaft.13. The apparatus according to claim 1, wherein the moveable elementextends between the first and second holes through a loop attached tothe atraumatic element.
 14. The apparatus according to claim 1, whereinthe moveable element extends along a length of the inner shaft and islongitudinally moveable within the shaft.
 15. The apparatus according toclaim 1, wherein the moveable element is a wire.
 16. The apparatusaccording to claim 1, wherein the atraumatic element is released bymovement of the moveable element away from the atraumatic element.
 17. Amethod of delivering a gastrointestinal device, the method comprising:passing a shaft through a length of the intestines, the shaft having anatraumatic element, distinct from the gastrointestinal device, distal toand releasably coupled to a distal tip of the shaft and having a releasemechanism that releasably engages the atraumatic element to retain theatraumatic element on the distal tip of the shaft; releasing theatraumatic element from the shaft and the release mechanism, the releasemechanism comprising a moveable element, the atraumatic element beingreleased from the distal tip of the shaft and the moveable element bymovement of the moveable element, the shaft including first and secondholes near its distal tip, the moveable element exiting the shaft viathe first hole and re-entering the shaft via the second hole; anddelivering the gastrointestinal device over the shaft, thegastrointestinal device comprising a tube extending over the shaft. 18.The method according to claim 17, wherein the shaft and gastrointestinaldevice are disposed within a guide tube, the guide tube configured toguide movement of the shaft and gastrointestinal device.
 19. The methodaccording to claim 18, wherein the guide tube guides the passage of theshaft and gastrointestinal device through a length of the stomach. 20.The method according to claim 17, wherein the shaft is disposed within alumen of the gastrointestinal device.
 21. The method according to claim17, wherein the atraumatic element is remotely releasable.
 22. Themethod according to claim 17, wherein the atraumatic element comprises aball.
 23. The method according to claim 17, wherein the atraumaticelement is inflatable.
 24. The method according to claim 17, wherein theatraumatic element is attached to a loop which is held by the releasemechanism.
 25. The method according to claim 17, wherein the atraumaticelement is larger in diameter than the shaft.
 26. The method accordingto claim 25, wherein the atraumatic element is 0.25 inches to 0.75inches in diameter.
 27. The method according to claim 17, wherein theshaft is a catheter having a lumen therein.
 28. The method according toclaim 17, wherein the shaft has a minimum bend radius of less than 0.5inches without kinking.
 29. The method according to claim 17, whereinthe moveable element extends along a first lumen in the shaft and a wireextends along a second lumen in the shaft.
 30. The method according toclaim 17, wherein the moveable element extends between the first andsecond holes through a loop attached to the atraumatic element.
 31. Themethod according to claim 17, wherein the moveable element extends alonga length of the inner shaft and is longitudinally moveable within theshaft.
 32. The method according to claim 17, wherein the atraumaticelement is released by movement of the moveable element away from theatraumatic element.
 33. The method according to claim 17, wherein thegastrointestinal device is delivered through an incision in the stomach.